Display device

ABSTRACT

A display device comprising: a plurality of source lines extending in a first direction; a plurality of gate lines extending in a second direction intersecting the first direction; a plurality of pixel electrodes arrayed in the first direction and the second direction; a plurality of common electrodes disposed corresponding to a plurality of touch regions arrayed in the first direction and the second direction, the plurality of common electrodes being disposed while opposed to the plurality of pixel electrodes; a plurality of sensor electrode lines electrically connected to the plurality of common electrodes; a plurality of inspection signal lines electrically connected to the plurality of common electrodes through a plurality of inspection thin film transistors; and an inspection gate line connected to a gate electrode of each of the plurality of inspection thin film transistors.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese application JP2019-014400, filed Jan. 30, 2019. This Japanese application isincorporated herein by reference.

BACKGROUND 1. Technical Field

The present disclosure relates to a display device.

2. Description of the Related Art

Conventionally, various display devices with a touch panel have beenproposed. Recently, what is called an in-cell type display device with atouch detection function in which a function of the touch panel isincorporated in the display panel is proposed in order to achieve makingthe whole display device thin. For example, the display device like thisis disclosed in U. S. Patent Application Publication No. 2016/0188063.U. S. Patent Application Publication No. 2016/0188063 discloses what iscalled a self-capacitance type touch detection that detects acapacitance generated between a common electrode and a finger when thefinger approaches the display panel.

SUMMARY

However, a configuration for detecting an electric connection failurebetween a plurality of common electrodes used to detect a touch positionhas not been implemented in the display device having the in-cell typetouch detection function and the self-capacitance type touch detectionfunction as disclosed in U. S. Patent Application Publication No.2016/0188063.

The present disclosure has been made in view of these problems, and anobject of the present disclosure is to implement a configuration fordetecting the electric connection failure between the plurality ofcommon electrodes used to detect the touch position in the displaydevice having the in-cell type and the self-capacitance type touchdetection function.

Solution to Problem

To solve the above problem, a display device comprising: a plurality ofsource lines extending in a first direction; a plurality of gate linesextending in a second direction intersecting the first direction; aplurality of pixel electrodes arrayed in the first direction and thesecond direction; a plurality of common electrodes disposedcorresponding to a plurality of touch regions arrayed in the firstdirection and the second direction, the plurality of common electrodesbeing disposed while opposed to the plurality of pixel electrodes; aplurality of sensor electrode lines electrically connected to theplurality of common electrodes; a plurality of inspection signal lineselectrically connected to the plurality of common electrodes through aplurality of inspection thin film transistors; and an inspection gateline connected to a gate electrode of each of the plurality ofinspection thin film transistors.

The configuration according to the present disclosure can implement aconfiguration for detecting the electric connection failure between theplurality of common electrodes used to detect the touch position in thedisplay device having the in-cell type and the self-capacitance typetouch detection function.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view illustrating a schematic configurationof display device according to the exemplary embodiment of the presentdisclosure.

FIG. 2 is a schematic plan view illustrating a configuration example ofdisplay panel according to the exemplary embodiment of the presentdisclosure.

FIG. 3 is a block diagram illustrating a configuration example of commonsensor driver according to the exemplary embodiment of the presentdisclosure.

FIG. 4 is a schematic diagram illustrating section A-A′ in FIG. 2 indisplay panel according to the exemplary embodiment of the presentdisclosure.

FIG. 5 is a schematic plan view illustrating a configuration example ofinspection circuit according to the exemplary embodiment of the presentdisclosure.

FIG. 6 is a schematic plan view illustrating an arrangement example ofcommon electrode connected to inspection circuit according to theexemplary embodiment of the present disclosure.

FIG. 7 is a schematic plan view illustrating another arrangement exampleof common electrode connected to inspection circuit according to theexemplary embodiment of the present disclosure.

FIG. 8 is a schematic plan view illustrating a configuration anotherexample of inspection circuit according to the exemplary embodiment ofthe present disclosure.

FIG. 9 is a schematic plan view illustrating another arrangement exampleof common electrode connected to inspection circuit according to theexemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, an exemplary embodiment of the present disclosure will bedescribed with reference to the drawings. FIG. 1 is a schematic planview illustrating a schematic configuration of display device 100according to the exemplary embodiment of the present disclosure. Displaydevice 100 includes display panel 10, first drive circuit 20, seconddrive circuit 30, control circuit 40, inspection circuit 50, a powersupply unit (not illustrated), and a backlight device (not illustrated).First drive circuit 20 and second drive circuit 30 may be included indisplay panel 10.

A plurality of source lines 11 extending in a first direction, aplurality of sensor electrode lines 12 extending in the first direction,and a plurality of gate lines 13 extending in a second directionintersecting with the first direction are provided in display panel 10.The plurality of source lines 11 are arranged at substantially equalintervals in the second direction, the plurality of sensor electrodelines 12 are arranged at substantially equal intervals in the seconddirection, and the plurality of gate lines 13 are arranged atsubstantially equal intervals in the first direction. Thin filmtransistor 14 is provided at each intersection of each source line 11and each gate line 13.

First drive circuit 20 includes source driver 21 that outputs a datasignal (display voltage) to each source line 11 and common sensor driver22 that outputs a common voltage and a sensor voltage to each sensorelectrode line 12. Source driver 21 and common sensor driver 22 may beconstructed with one IC (Integrated Circuit) or constructed with twoindependent ICs. Second drive circuit 30 includes gate driver 31 thatoutputs a gate signal (scan signal) to each gate line 13.

In display panel 10, a plurality of pixels 15 are arranged in the firstdirection and the second direction while corresponding to theintersections of source lines 11 and gate lines 13. Although detailswill be described later, display panel 10 includes a thin filmtransistor substrate, a color filter substrate, and a liquid crystallayer sandwiched between the two substrates. In the thin film transistorsubstrate, pixel electrode 16 is provided according to each pixel 15.That is, pixel electrodes 16 are arrayed in the first direction and thesecond direction. In the thin film transistor substrate, commonelectrodes 17 are disposed at a ratio of one per the plurality of pixels15 so as to be opposed to the plurality of pixel electrodes 16. Eachcommon electrode 17 has a function as an electrode used for displayingthe image and a function as an electrode (sensor electrode) used fordetecting a touch position. That is, display panel 10 has an imagedisplay function and a touch detection function. Common electrode 17 isdisposed corresponding to each of the plurality of touch regions arrayedin the first direction and the second direction.

FIG. 2 is a schematic plan view illustrating a configuration example ofdisplay panel 10 of the exemplary embodiment. In FIG. 2, source line 11and source driver 21 are omitted for convenience. In the example of FIG.2, the plurality of common electrodes 17 are provided at a rate of oneper every group of 16 pixels 15 including four pixels 15 in the firstdirection and four pixels 15 in the second direction. Actually, forexample, common electrodes 17 may be provided at a ratio of one perevery several hundred pixels 15. However, for convenience, commonelectrodes 17 are provided at a rate of one per every group of 16 pixels15 in FIG. 2. The plurality of common electrodes 17 have substantiallythe same shape, and are regularly arrayed. In planar view, each commonelectrode 17 overlaps a plurality of sensor electrode lines 12, and iselectrically connected to one of the plurality of sensor electrode lines12 through through-hole 18. In the configuration of FIG. 2, commonelectrode 17 a overlaps three sensor electrode lines 12 a, 12 b, 12 c,and is electrically connected to one of sensor electrode lines 12 athrough through-hole 18 a. Common electrode 17 b overlaps three sensorelectrode lines 12 a, 12 b, 12 c, and is electrically connected to oneof sensor electrode lines 12 b through through-hole 18 b.

FIG. 3 is a block diagram illustrating a configuration example of commonsensor driver 22 of the exemplary embodiment. Common sensor driver 22includes common voltage generator 221, sensor voltage generator 222,timing controller 223, monitor 224, and position detector 225. Theconfiguration of common sensor driver 22 is not limited to the exemplaryembodiment, but a known configuration can be adopted.

Common voltage generator 221 generates a common voltage (referencevoltage) for image display. Common sensor driver 22 supplies thegenerated common voltage to common electrode 17 through sensor electrodeline 12 during a writing period in which the data signal (displayvoltage) is supplied to pixel electrode 16. Sensor voltage generator 222generates a sensor voltage detecting the touch position. Common sensordriver 22 supplies the generated sensor voltage to common electrode 17through sensor electrode line 12 in a non-writing period after thewriting period. Timing controller 223 controls timing at which commonsensor driver 22 outputs the common voltage and the sensor voltage basedon a timing signal (horizontal synchronizing signal and verticalsynchronizing signal) received from control circuit 40. Monitor 224monitors (measures) current (charge) when the sensor voltage is suppliedto common electrode 17. Position detector 225 detects a coordinate ofthe touch position based on a measurement result of monitor 224. In FIG.3, position detector 225 is provided inside common sensor driver 22, butmay be provided inside control circuit 40.

An example of a touch position detection method will be described below.Display device 100 detects the touch position by a self-capacitancemethod of a capacitive system. Specifically, when a finger approaches asurface of display panel 10, capacitance is generated between commonelectrode (sensor electrode) 17 and the finger. When the capacitance isgenerated, parasitic capacitance in common electrode 17 increases, andthe current (charge) increases when the sensor voltage is supplied tocommon electrode 17. Common sensor driver 22 detects the position, thatis, the coordinate of contact with display panel 10 based on afluctuation amount of the current (charge). A known method can beadopted to a self-capacitance type touch position detection method. Thedetection of the touch position may be performed in a non-displayperiod.

An example of a sectional structure of display panel 10 will bedescribed below with reference to FIG. 4. Various sectional structurescan be applied to display panel 10. In the exemplary embodiment, astructure in which common electrode (sensor electrode) 17 is disposed ina layer below pixel electrode 16 (on back surface side) will bedescribed by way of example. Alternatively, common electrode (sensorelectrode) 17 may be disposed in a layer above pixel electrode 16 (ondisplay surface side).

FIG. 4 is a schematic diagram illustrating section A-A′ in FIG. 2 indisplay panel 10 of the exemplary embodiment. Display panel 10 includesthin film transistor substrate 200, color filter substrate 300, andliquid crystal layer 400 sandwiched between the two substrates.

In thin film transistor substrate 200, a plurality of gate lines 13 (notillustrated) are formed on glass substrate 201, first insulating film202 is formed so as to cover the plurality of gate lines 13, a pluralityof source lines 11 are formed on first insulating film 202, secondinsulating film 203 is formed so as to cover the plurality of sourcelines 11, and third insulating film 204 is formed on second insulatingfilm 203. For example, third insulating film 204 is made of aphotosensitive organic material mainly containing acryl. A plurality ofcommon electrodes 17 are formed on third insulating film 204, fourthinsulating film 205 is formed so as to cover the plurality of commonelectrodes 17, and through-hole 18 is made in a part of fourthinsulating film 205. Adjacent common electrodes 17 are not electricallyconnected to each other because fourth insulating film 205 is disposedbetween the adjacent common electrodes 17. A plurality of sensorelectrode lines 12 are formed on fourth insulating film 205 and inthrough-hole 18, and fifth insulating film 206 is formed so as to coverthe plurality of sensor electrode lines 12, and a plurality of pixelelectrodes 16 are formed on fifth insulating film 206. Sensor electrodeline 12 is formed at a position overlapping source line 11 in planarview. Sensor electrode line 12 may be formed at a position that does notoverlap source line 11 in planar view. For example, in planar view,sensor electrode line 12 may be disposed side by side with source line11, or disposed so as to partially overlap source line 11. In planarview, thin film transistor substrate 200 may include a combination ofsensor electrode lines 11 that overlap source lines 12 and sensorelectrode lines 12 that do not overlap source lines 11. Sensor electrodeline 12 is electrically connected to common electrode 17 throughthrough-hole 18. Because fourth insulating film 205 is disposed betweensensor electrode line 12 and common electrode 17, sensor electrode line12 is not electrically connected to common electrodes 17 except forcommon electrode 17 electrically connected to sensor electrode line 12through through-hole 18. A slit is formed in pixel electrode 16.Although not illustrated, an alignment film is formed on pixel electrode16, and a polarizing plate is formed outside glass substrate 201. Aliquid crystal capacitance is formed between pixel electrode 16 andcommon electrode 17.

In color filter substrate 300, black matrix 302 is formed on glasssubstrate 301. Although not illustrated, a color filter is formed onglass substrate 301, an overcoat film is formed so as to cover the colorfilter, and the alignment film is formed on the overcoat film. Thepolarizing plate is formed outside color filter substrate 300.

In display device 100, an electric field generated between pixelelectrode 16 and common electrode 17 is applied to liquid crystal layer400 to drive the liquid crystal, whereby an amount of light passingthrough liquid crystal layer 400 is adjusted to display the image.

As described above with reference to FIG. 1, display device 100 of thepresent disclosure includes inspection circuit 50, and can detect anelectric connection failure between the plurality of common electrodes17 used for the touch detection using inspection circuit 50.

FIG. 5 is a schematic plan view illustrating a configuration example ofinspection circuit 50 of the exemplary embodiment of the presentdisclosure. FIG. 6 is a schematic plan view illustrating an arrangementexample of common electrode 17 (common electrode C11 to common electrodeC56) connected to inspection circuit 50 of the exemplary embodiment.

As illustrated in FIG. 5, inspection circuit 50 includes a plurality ofinspection signal lines 51 (inspection signal line 51A to inspectionsignal line 51F), a plurality of inspection gate lines 52 (inspectiongate line 52A to inspection gate line 52E), and a plurality ofinspection thin film transistors 53. The plurality of inspection signallines 51 are electrically connected to the plurality of commonelectrodes 17 (common electrode C11 to common electrode C56) through theplurality of inspection thin film transistors 53 and the plurality ofsensor electrode lines 12 extending in the first direction. Numbers ofcommon electrodes 17 (common electrode C11 to common electrode C56) inFIG. 5 has a correspondence relation numbers of common electrode 17(common electrode C11 to common electrode C56) in FIG. 6. The pluralityof inspection gate lines 52 are connected to gate electrodes of theplurality of inspection thin film transistors 53, and control on-off ofinspection thin film transistor 53. In the exemplary embodiment, eachinspection gate line 52 is connected to the gate electrodes of sixinspection thin film transistors 53. Although the plurality ofinspection signal lines 51 may be connected to the plurality of commonelectrodes 17 through wirings different from the plurality of sensorelectrode lines 12, desirably the plurality of inspection signal lines51 are connected to the plurality of common electrodes 17 through theplurality of sensor electrode lines 12 to be able to decrease the numberof wirings extending in display panel 10. The electric connectionfailure due to disconnection of the plurality of sensor electrode lines12 can be detected by connecting the plurality of inspection signallines 51 to the plurality of common electrodes 17 through the pluralityof sensor electrode lines 12.

Numeral x in each common electrode Cxy means which inspection gate line52 is connected to common electrode Cxy. Numeral x of 1 means thatcommon electrode Cxy is connected to inspection gate line 52A. Numeral xof 2 means that common electrode Cxy is connected to inspection gateline 52B. Numeral x of 3 means that common electrode Cxy is connected toinspection gate line 52C. Numeral x of 4 means that common electrode Cxyis connected to inspection gate line 52D. Numeral x of 5 means thatcommon electrode Cxy is connected to inspection gate line 52E.

Number y in each common electrode Cxy means which inspection signal line51 is connected to common electrode Cxy. For example, numeral y of 1means that common electrode Cxy is connected to inspection signal line51A. Numeral y of 2 means that common electrode Cxy is connected toinspection signal line 51B. Numeral y of 3 means that common electrodeCxy is connected to inspection signal line 51C. Numeral y of 4 meansthat common electrode Cxy is connected to inspection signal line 51D.Numeral y of 5 means that common electrode Cxy is connected toinspection signal line 51E. Numeral y of 6 means that common electrodeCxy is connected to inspection signal line 51F.

As illustrated in FIG. 6, the plurality of common electrodes 17 includethe plurality of common electrodes 17 arrayed in the first direction. Inthe example of FIG. 6, the plurality of common electrodes 17 (commonelectrode C11 to common electrode C55) are arrayed in the firstdirection as a first column, and the plurality of common electrodes 17(common electrode C12 to common electrode C56) are arrayed in the firstdirection as a second column. In the example of FIG. 6, the first columnand the second column are repeatedly arranged in the second direction indisplay panel 10.

As illustrated in FIG. 6, the plurality of common electrodes 17 includethe plurality of common electrodes 17 arrayed in the second direction.In the example of FIG. 6, for example, two common electrodes 17 (commonelectrode C11 and common electrode C12) are arrayed in the seconddirection so as to be repeatedly arranged.

As illustrated in FIG. 5, the plurality of inspection thin filmtransistors 53 are connected to the plurality of common electrodes 17through the plurality of sensor electrode lines 12 extending in thefirst direction. First to fifteenth sensor electrode lines 12 from theleft in FIG. 5 are connected to the plurality of common electrodes 17(common electrode C11 to common electrode C55) in the first column inFIG. 6, and sixteenth to thirtieth sensor electrode lines 12 from theleft in FIG. 5 are connected to the plurality of common electrodes 17(common electrode C12 to common electrode C56) in the second column inFIG. 6. First to fifteenth sensor electrode lines 12 from the left inFIG. 5 extend in the first direction so as to overlap the plurality ofcommon electrodes 17 (common electrode C11 to common electrode C55) inthe first column in FIG. 6 in planar view. For example, first sensorelectrode line 12 from the left in FIG. 5 is connected to commonelectrode C11 in FIG. 6, and fifteenth sensor electrode line 12 from theleft in FIG. 5 is connected to common electrode C55 in FIG. 6.Similarly, sixteenth to thirtieth sensor electrode lines 12 from theleft in FIG. 5 extend in the first direction so as to overlap theplurality of common electrodes 17 (common electrode C12 to commonelectrode C56) in the second column in FIG. 6 in planar view. Forexample, the sixteenth sensor electrode line 12 from the left in FIG. 5is connected to common electrode C12 in FIG. 6, and thirtieth sensorelectrode line 12 from the left in FIG. 5 is connected to commonelectrode C56 in FIG. 6.

As illustrated in FIG. 5, the plurality of common electrodes 17 (forexample, common electrode C11 to common electrode C55) arrayed in thefirst direction are connected to different inspection thin filmtransistors 53. As illustrated in FIG. 5, the plurality of commonelectrodes 17 (for example, common electrode C11 and common electrodeC12) adjacent to each other in the second direction are connected todifferent inspection thin film transistors 53.

Two common electrodes 17 (for example, common electrode C11 and commonelectrode C13) adjacent to each other in the first direction areconnected to different inspection signal lines 51. For example, commonelectrode C11 and common electrode C13 in FIG. 6 are adjacent to eachother in the first direction, and as illustrated in FIG. 5, commonelectrode C11 is connected to inspection signal line 51A while commonelectrode C13 is connected to inspection signal line 51C. Thisrelationship is satisfied not only between common electrode C11 andcommon electrode C13, but also in all the plurality of common electrodes17 (for example, common electrode C11 to common electrode C55) arrayedin the first direction.

Two common electrodes 17 (for example, common electrode C11 and commonelectrode C12) adjacent to each other in the second direction areconnected to different inspection signal lines 51. For example, commonelectrode C11 and common electrode C12 in FIG. 6 are adjacent to eachother in the second direction, and as illustrated in FIG. 5, commonelectrode C11 is connected to inspection signal line 51A while commonelectrode C12 is connected to inspection signal line 51B. Thisrelationship is satisfied not only between common electrode C11 andcommon electrode C12 but also in all the plurality of common electrodes17 arrayed in the second direction.

In the exemplary embodiment, the first common electrode (for example,common electrode C14) included in the plurality of common electrodes 17is connected to inspection signal line 51 different from inspectionsignal lines 51 connected to the other common electrodes 17 disposedadjacent to a periphery of the first common electrode (for example,common electrode C14) among inspection signal lines 51. For example,when common electrode C14 is taken as the first common electrode, commonelectrode 17 disposed adjacent to the periphery of common electrode C14includes a total of eight common electrodes (two common electrodes C11,one common electrode C12, two common electrodes C13, two commonelectrodes C15, and one common electrode C16). As illustrated in FIG. 5,common electrode C14 that is the first common electrode is connected toinspection signal line 51D through inspection thin film transistor 53.On the other hand, common electrode C11 is connected to inspectionsignal line 51A through inspection thin film transistor 53, and commonelectrode C12 is connected to inspection signal line 51B throughinspection thin film transistor 53, common electrode C13 is connected toinspection signal line 51C through inspection thin film transistor 53,common electrode C15 is connected to inspection signal line 51E throughinspection thin film transistor 53, and common electrode C16 isconnected to inspection signal line 51F through inspection thin filmtransistor 53. That is, when common electrode C14 is taken as the firstcommon electrode, common electrode 17 disposed adjacent to the peripheryof common electrode C14 is connected to inspection signal lines 51except for inspection signal line 51A to which common electrode C14 isconnected through inspection thin film transistor 53.

In the exemplary embodiment, the signal having the same polarity isapplied to inspection signal lines 51A, 51D, 51E. The signal having thesame polarity is applied to inspection signal lines 51B, 51C, 51F, andthe signal having an opposite polarity is applied to inspection signallines 51A, 51D, 51E. As a specific example, when a +5-V signal isapplied to inspection signal lines 51A, 51D, 51E, a −5-V signal isapplied to inspection signal lines 51B, 51C, 51F.

Then, the signals having the different polarities are applied to twocommon electrodes 17 (for example, common electrode C11 and commonelectrode C13) adjacent to each other in the first direction through theplurality of inspection signal lines 51. For example, common electrodeC11 is connected to inspection signal line 51A through inspection thinfilm transistor 53. As illustrated in FIG. 6, common electrode C13adjacent to common electrode C11 in the first direction is connected toinspection signal line 51C through inspection thin film transistor 53.As described above, because the signals having opposite polarities areapplied to inspection signal line 51A and inspection signal line 51C,the signals having the opposite polarities are applied to commonelectrode C11 and common electrode C13 adjacent to each other in thefirst direction.

Then, the signals having the different polarities are applied to twocommon electrodes 17 (for example, common electrode C11 and commonelectrode C12) adjacent to each other in the second direction throughthe plurality of inspection signal lines 51. For example, commonelectrode C11 is connected to inspection signal line 51A throughinspection thin film transistor 53. As illustrated in FIG. 6, commonelectrode C12 adjacent to common electrode C11 in the second directionis connected to inspection signal line 51B through inspection thin filmtransistor 53. As described above, because the signals having theopposite polarities are applied to inspection signal line 51A andinspection signal line 51B, the signals having the opposite polaritiesare applied to common electrode C11 and common electrode C12 adjacent toeach other in the second direction.

In the exemplary embodiment, the combination of inspection gate line 52and inspection signal line 51 connected to first common electrode 17included in the plurality of common electrodes 17 (for example, commonelectrode C11 to common electrode C55) arrayed in the first direction isdifferent from the combination of inspection gate line 52 and inspectionsignal line 51 connected to another common electrodes 17 included in theplurality of common electrodes 17 arrayed in the first direction. Forexample, common electrode C11 is connected to inspection gate line 52Aand inspection signal line 51A, but common electrode 17 connected toboth inspection gate line 52A and inspection signal line 51A does notexist in other common electrodes 17 included in the first column in FIG.6. As described above, numeral x in each common electrode Cxy meanswhich inspection gate line 52 is connected to common electrode Cxy, andthe numeral y in each common electrode Cxy means which inspection signalline 51 is connected to common electrode Cxy. Thus, in the first columnof FIG. 6, the same numerals x and y do not exist in each commonelectrode Cxy.

With this configuration, the electric connection failure can accuratelybe detected between the plurality of common electrodes 17 arrayed in thefirst direction. For example, when at least two combinations ofinspection gate lines 52 and inspection signal lines 51 to be connectedexist in the plurality of common electrodes 17 included in the firstcolumn, the same inspection signal is input to at least two commonelectrodes 17 at the same timing. On the other hand, in theconfiguration of the exemplary embodiment, the same inspection signal isnot input to the plurality of common electrodes 17 arrayed in the firstdirection at the same timing. As a result, the electric connectionfailure can accurately be detected between the plurality of commonelectrodes 17 in the first direction.

In the exemplary embodiment, the combination of inspection gate line 52and inspection signal line 51 connected to one (for example, commonelectrode C11) of two common electrodes 17 (for example, commonelectrode C11 and common electrode C12) adjacent to each other in thesecond direction is different from the combination of inspection gateline 52 and inspection signal line 51 connected to the other (forexample, common electrode C12) of two common electrodes 17 (for example,common electrode C11 and common electrode C12) adjacent to each other inthe second direction. That is, in FIG. 6, two common electrodes Cxyadjacent to each other in the second direction are different from eachother in at least one of numerals x and y in each common electrode Cxy.

In display device 100 including inspection circuit 50, a method fordetecting the electric connection failure between the plurality ofcommon electrodes 17 used for the touch detection will be describedbelow.

As a first step, a transistor control signal turning on inspection thinfilm transistor 53 is input to inspection gate line 52A in FIG. 5.Consequently, inspection thin film transistor 53 connected so as to beinterposed between inspection gate line 52A and common electrodes C11,C12, C13, C14, C15, C16 is turned on.

Subsequently, as a second step, the inspection signal is input to eachinspection signal line 51. As described above, in the exemplaryembodiment, the signal having the same polarity is applied to inspectionsignal lines 51A, 51D, 51E. The signal having the same polarity isapplied to inspection signal lines 51B, 51C, 51F, and the signal havingan opposite polarity is applied to inspection signal lines 51A, 51D,51E. For this reason, when the +5-V signal is applied to inspectionsignal lines 51A, 51D, 51E, the −5-V signal is applied to inspectionsignal lines 51B, 51C, 51F.

In the second step, potentials at the plurality of pixel electrodes 16disposed so as to be opposed to common electrode 17 are set to 0 V, forexample. Thus, with the input of the inspection signal, a potentialdifference is generated between each common electrode 17 and pixelelectrode 16, and the liquid crystal is driven in the touch regiondefined by each common electrode 17, whereby the amount of light passingthrough liquid crystal layer 400 is changed to display the image. Theelectric connection failure can be detected between the plurality ofcommon electrodes 17 by inspecting this image display state.

For example, when a short circuit is generated between common electrodeC11 and common electrode C13 due to existence of dust between variouswires (for example, sensor electrode line 12) and common electrode 17,because the signal applied to common electrode C11 and the signalapplied to common electrode C13 have the opposite polarities, theopposite polarities cancel each other, and the potentials at commonelectrode C11 and common electrode C13 become 0 V. For this reason, thepotential difference is not generated between common electrode C11 andthe plurality of pixel electrodes 16 and between common electrode C13and the plurality of pixel electrodes 16, and the liquid crystal is notdriven. The amount of light passing through liquid crystal layer 400 isnot changed, and the desired image is not displayed. In this way, theelectric connection failure can be detected between the plurality ofcommon electrodes 17.

Subsequently, as a third step, the transistor control signal turning offinspection thin film transistor 53 is input to inspection gate line 52A.Consequently, inspection thin film transistor 53 connected so as to beinterposed between inspection gate line 52A and common electrodes C11,C12, C13, C14, C15, C16 is turned off.

As a fourth step, the transistor control signal turning on inspectionthin film transistor 53 is input to inspection gate line 52B.Consequently, inspection thin film transistor 53 connected so as to beinterposed between inspection gate line 52B and common electrodes C21,C22, C23, C24, C25, C26 is turned on.

Subsequently, similarly to the second step, the inspection signal isinput to each inspection signal line 51 as a fifth step. In the fifthstep, the potentials at the plurality of pixel electrodes 16 disposed soas to be opposed to common electrode 17 are set to 0 V, for example.Thus, with the input of the inspection signal, a potential difference isgenerated between each common electrode 17 and pixel electrode 16, andthe liquid crystal is driven in the touch region defined by each commonelectrode 17, whereby the amount of light passing through liquid crystallayer 400 is changed to display the image. The electric connectionfailure can be detected between the plurality of common electrodes 17 byinspecting this image display state.

For example, when a short circuit is generated between common electrodeC22 and common electrode C21 due to existence of dust between variouswires (for example, sensor electrode line 12) and common electrode 17,because the signal applied to common electrode C22 and the signalapplied to common electrode C21 have the opposite polarities, theopposite polarities cancel each other, and the potentials of commonelectrode C22 and common electrode C21 become 0 V. For this reason, thepotential difference is not generated between common electrode C22 andthe plurality of pixel electrodes 16 and between common electrode C21and the plurality of pixel electrodes 16, and the liquid crystal is notdriven. The amount of light passing through liquid crystal layer 400 isnot changed, and the desired image is not displayed. In this way, theelectric connection failure can be detected between the plurality ofcommon electrodes 17.

Subsequently, as a sixth step, the transistor control signal turning offinspection thin film transistor 53 is input to inspection gate line 52B.Consequently, inspection thin film transistor 53 connected so as to beinterposed between inspection gate line 52B and common electrodes C21,C22, C23, C24, C25, C26 is turned off.

In this way, the electric connection failure can be detected between theplurality of common electrodes 17 in all the touch regions by repeatingthe step of inputting the transistor control signal turning oninspection thin film transistor 53 to inspection gate line 52, the stepof inputting the inspection signal to inspection signal line 51, and thestep of inputting the transistor control signal turning off inspectionthin film transistor 53 to inspection gate line 52.

In repeating the above steps, desirably the polarity of the inspectionsignal input to inspection signal line 51 is opposite to the polarity ofthe previously-applied inspection signal. For example, in the secondstep, when the +5-V signal is applied to inspection signal lines 51A,51D, 51E while the −5-V signal is applied to inspection signal lines51B, 51C, 51F, desirably the −5-V signal is applied to inspection signallines 51A, 51D, 51E while the +5-V signal is applied to inspectionsignal lines 51B, 51C, 51F in next inputting the inspection signal toinspection signal line 51. Degradation of liquid crystal moleculescontained in liquid crystal layer 400 can be prevented by adopting themethod.

In the exemplary embodiment, inspection circuit 50 includes theplurality of inspection gate lines 52, and the gate electrodes of theplurality of inspection thin film transistors 53 are connected to one ofthe plurality of inspection gate lines 52. Alternatively, as illustratedin FIG. 8, inspection circuit 50 may include only one inspection gateline 52.

However, all inspection signal lines 51 connected to the plurality ofcommon electrodes 17 included in the first column vary in order toaccurately detect the electric connection failure between the pluralityof common electrodes 17 included in the first column. For this reason,when inspection circuit 50 includes only one inspection gate line 52,for example, when 15 common electrodes 17 are included in the firstcolumn, desirably 15 inspection signal lines 51 are provided asillustrated in FIG. 8.

In the configuration of FIG. 8, for example, the +5-V inspection signalis applied to inspection signal lines 51 disposed in odd numbers fromthe top, and for example the −5-V inspection signal is applied toinspection signal lines 52 disposed in even numbers from the top.

As illustrated in FIG. 9, when common electrode 17 disposed in the firstrow of the first column is common electrode C101 connected to inspectionsignal line 51 (for example, inspection signal line 51A) disposed in theodd number (for example, the first) from the top, common electrode C102adjacent to common electrode C101 in the first direction is connected toinspection signal line 51 (for example, inspection signal line 51B)disposed in the even number (for example, second) from the top. Withthis configuration, the polarities of the inspection signals applied totwo common electrodes 17 (for example, common electrode C101 and commonelectrode C102) adjacent to each other in the first direction can beopposite to each other.

As illustrated in FIG. 9, when common electrode 17 disposed in the firstcolumn is common electrode C101 connected to inspection signal line 51(for example, inspection signal line 51A) disposed in the odd number(for example, the first) from the top, common electrode C104 that isdisposed in the second column and is adjacent to common electrode C101in the second direction is connected to inspection signal line 51 (forexample, inspection signal line 51D) disposed in the even number (forexample, fourth) from the top. With this configuration, the polaritiesof the inspection signals applied to two common electrodes 17 (forexample, common electrode C101 and common electrode C104) adjacent toeach other in the second direction can be opposite to each other.

Even in the examples of FIGS. 8 and 9, the combination of inspectiongate line 52 and inspection signal line 51 connected to the first commonelectrode (for example, common electrode C101) included in the pluralityof common electrodes 17 (for example, common electrode C101 to commonelectrode C115) arrayed in the first direction can be different from thecombination of inspection gate line 52 and inspection signal line 51connected to another common electrodes 17 included in the plurality ofcommon electrodes 17 (for example, common electrode C101 to commonelectrode C115) arrayed in the first direction. For example, commonelectrode C101 is connected to inspection signal line 51A disposed atthe top in FIG. 8, but common electrode 17 connected to the inspectionsignal line 51A does not exist in another common electrode 17 includedin the first column in FIG. 9. That is, in the configurations of FIGS. 8and 9, all inspection signal lines 51 to be connected to the pluralityof common electrodes 17 arrayed in the first direction vary because onlyone inspection gate line 52 exists.

Even in the example of FIGS. 8 and 9, the combination of inspection gateline 52 and inspection signal line 51 connected to one (for example,common electrode C101) of two common electrodes 17 (for example, commonelectrode C101 and common electrode C104) adjacent to each other in thesecond direction can be different from the combination of inspectiongate line 52 and inspection signal line 51 connected to the other (forexample, common electrode C104) of two common electrodes 17 (forexample, common electrode C101 and common electrode C104) adjacent toeach other in the second direction. That is, in the configurations ofFIGS. 8 and 9, inspection signal lines 51 connected to two commonelectrodes 17 adjacent to each other in the second direction varybecause only one inspection gate line 52 exists. That is, in FIG. 9, twocommon electrodes Cxy adjacent to each other in the second direction aredifferent from each other in numeral y in each common electrode Cxy. InFIG. 9, x is displayed in 1 digit, and y is displayed in 2 digits.

However, as described above, in the configuration of FIG. 8, forexample, when 15 common electrodes 17 are included in the first column,desirably 15 inspection signal lines 51 are provided as illustrated inFIG. 8. For this reason, the total number of inspection signal lines 51and inspection gate lines 52 becomes 16, an area of inspection circuit50 and an area of a frame region in the display panel are hardlyreduced.

On the other hand, as illustrated in FIG. 5, inspection circuit 50includes the plurality of inspection gate lines 52, and the gateelectrodes of the plurality of inspection thin film transistors 53 areconnected to one of the plurality of inspection gate lines 52, whichallows the decrease of the total number of inspection signal lines 51and inspection gate lines 52. That is, a product of inspection signalline 51 and inspection gate line 52 may be greater than or equal to thenumber of common electrodes 17 included in the first column in orderthat the combination of inspection signal line 51 and inspection gateline 52 connected to each common electrode 17 varies to detect theelectric connection failure between the plurality of common electrodes17 included in the first column. Thus, in the exemplary embodiment inwhich 15 common electrodes 17 are included in the first column, forexample, when three inspection gate lines 52 and five inspection signallines 51 exist, the product becomes 15, and the electric connectionfailure can be detected between the plurality of common electrodes 17included in the first column. That is, when the total number ofinspection signal lines 51 and inspection gate lines 52 becomes eight inthe minimum configuration. When the number of common electrodes 17included in the first column is N, the total number of inspection signallines 51 and inspection gate lines 52 can be decreased by preparing anintegral number of inspection signal lines 51 close to N (½) and anintegral number of inspection gate lines 52 close to N (½), a product ofthe integral number of inspection signal lines 51 and the integralnumber of inspection gate lines 52 becoming N.

However, in the exemplary embodiment, in order that the number ofinspection signal lines 51 to which the inspection signal having thesame polarity as inspection signal line 51A is input is equal to thenumber of inspection signal lines 51 to which the inspection signalhaving the polarity opposite to inspection signal line 51A is input, sixinspection signal lines 51 are provided to set the number of inspectionsignal lines 51 to the even number, and the inspection signal is inputto two-column common electrodes 17. In this way, the number ofinspection signal lines 51 to which the inspection signal having one ofthe polarities is input is equal to the number of inspection signallines 51 to which the inspection signal of the other polarity is input.Consequently, even if the charge is generated by inputting theinspection signal to each inspection signal lines 51, the electriccharges generated in display panel 10 can be canceled as a whole, anddisplay unevenness can be prevented.

In the configuration of FIG. 6, the plurality of common electrodes 17(common electrode C11 to common electrode C55) are arrayed in the firstdirection as the first column, the plurality of common electrodes 17(common electrode C12 to common electrode C56) are arrayed in the firstdirection as the second column, and the first column and the secondcolumn are repeatedly disposed in the second direction in display panel10. However, the present disclosure is not limited to the configurationin FIG. 6.

For example, in the configuration of FIG. 7, the plurality of commonelectrodes 17 (common electrode C11 to common electrode C55) are arrayedin the second direction as the first column, and the plurality of commonelectrodes 17 (common electrode C12 to common electrode C56) are arrayedin the second direction as the second column. The first column and thesecond column are repeatedly disposed in the first direction in displaypanel 10.

In the configuration of FIG. 7, the combination of inspection gate line52 and inspection signal line 51 connected to the first common electrodeincluded in the plurality of common electrodes 17 (for example, commonelectrode C11 to common electrode C55) arrayed in the second directionmay be different from the combination of inspection gate line 52 andinspection signal line 51 connected to another common electrode 17included in the plurality of common electrodes 17 arrayed in the seconddirection. For example, common electrode C11 is connected to inspectiongate line 52A and inspection signal line 51A, but common electrode 17connected to both inspection gate line 52A and inspection signal line51A does not exist in another common electrode 17 included in the firstcolumn arrayed in the second direction in FIG. 7. As described above,numeral x in each common electrode Cxy means which inspection gate line52 is connected to common electrode Cxy, and the numeral y in eachcommon electrode Cxy means which inspection signal line 51 is connectedto common electrode Cxy. Thus, common electrode Cxy in which both thenumber x and the number y are the same may not exist in the first columnin FIG. 7.

In the above, the specific embodiments of the present application havebeen described, but the present application is not limited to theabove-mentioned embodiments, and various modifications may be made asappropriate without departing from the spirit of the presentapplication.

What is claimed is:
 1. A display device comprising: a plurality ofsource lines extending in a first direction; a plurality of gate linesextending in a second direction intersecting the first direction; aplurality of pixel electrodes arrayed in the first direction and thesecond direction; a plurality of common electrodes disposedcorresponding to a plurality of touch regions arrayed in the firstdirection and the second direction, the plurality of common electrodesbeing disposed while opposed to the plurality of pixel electrodes; aplurality of sensor electrode lines electrically connected to theplurality of common electrodes; a plurality of inspection signal lineselectrically connected to the plurality of common electrodes through aplurality of inspection thin film transistors; and an inspection gateline connected to a gate electrode of each of the plurality ofinspection thin film transistors.
 2. The display device according toclaim 1, wherein the plurality of common electrodes arrayed in the firstdirection are connected to different inspection thin film transistors.3. The display device according to claim 2, wherein two commonelectrodes adjacent to each other in the second direction are connectedto different inspection thin film transistors.
 4. The display deviceaccording to claim 1, wherein two common electrodes adjacent to eachother in the first direction are connected to different inspectionsignal lines.
 5. The display device according to claim 4, wherein twocommon electrodes adjacent to each other in the second direction areconnected to different inspection signal lines.
 6. The display deviceaccording to claim 1, wherein two common electrodes adjacent to eachother in the second direction are connected to different inspectionsignal lines.
 7. The display device according to claim 1, wherein afirst common electrode included in the plurality of common electrodes isconnected to an inspection signal line different from the inspectionsignal line connected to the common electrode disposed adjacent to aperiphery of the first common electrode among the inspection signallines.
 8. The display device according to claim 1, wherein two commonelectrodes adjacent to each other in the first direction are differentfrom each other in a polarity of a signal applied through the pluralityof inspection signal lines.
 9. The display device according to claim 8,wherein two common electrodes adjacent to each other in the seconddirection are different from each other in the polarity of the signalapplied through the plurality of inspection signal lines.
 10. Thedisplay device according to claim 1, wherein two common electrodesadjacent to each other in the second direction are different from eachother in a polarity of a signal applied through the plurality ofinspection signal lines.
 11. The display device according to claim 1,wherein the inspection gate line is a plurality of inspection gatelines, and the gate electrodes of the plurality of inspection thin filmtransistors are connected to one of the plurality of inspection gatelines.
 12. The display device according to claim 11, wherein oneinspection gate line included in the plurality of inspection gate linesis connected to the gate electrodes of at least two inspection thin filmtransistors included in the plurality of inspection thin filmtransistors.
 13. The display device according to claim 11, wherein acombination of the inspection gate line and the inspection signal lineconnected to a first common electrode included in the plurality ofcommon electrodes arrayed in the first direction is different from acombination of the inspection gate line and the inspection signal lineconnected to another common electrodes included in the plurality ofcommon electrodes arrayed in the first direction.
 14. The display deviceaccording to claim 11, wherein a combination of the inspection gate lineand the inspection signal line connected to one of the two commonelectrodes adjacent to each other in the second direction is differentfrom a combination of the inspection gate line and the inspection signalline connected to another one of the two common electrodes adjacent toeach other in the second direction.
 15. The display device according toclaim 11, wherein a combination of the inspection gate line and theinspection signal line connected to a first common electrode included inthe plurality of common electrodes arrayed in the second direction isdifferent from a combination of the inspection gate line and theinspection signal line connected to another common electrode included inthe plurality of common electrodes arrayed in the second direction. 16.The display device according to claim 1, wherein the plurality ofinspection signal lines are electrically connected to the plurality ofcommon electrodes through the plurality of sensor electrode lines.